Steam generating apparatus



Nov. 6, 1951 p, ARAN-r 2,574,368

STEAM GENERATING APPARATUS Nov. 6, 1951 Filed Aug. 28, 1943 P. ARANT STEAM GENERATING APPARATUS allglllllllll' Il-IIIIIHHI 3 She ets-Sheet 2 Nov. 6, 1951 P. ARANT 2,574,368

STEAM GEINERATINGl APPARATUS' A Filed Aug. 28, 1943 3 Sheets-Sheet 3 www# Patented Nov. 6, 1 951 STEAM GENERATIN G APPARATUS Perry Arant, Alhambra, Calif., assignor to Clayton Manufacturing Company, Alhambra, Calif.

Application August 28, 1943, Serial No. 500,413

22 Claims. (Cl. 122-411) The present invention relates to steam generating apparatus, and more particularly to a novel system of feed water supply and recirculation for use with a, steam generating unit and steam separator, whereby a maximum of efficiency in operation can be attained.

The principal object of the invention is to provide a steam generating system in which heat losses are reduced to a minimum.

Another object of the invention is to eliminate the hot well heretofore used in steam generating apparatusto receive trapped-out liquid and accompanying vapor from a steam separator, and thereby avoid the escape of such vapor and the loss of its heat content to the atmosphere. In this connection, and aside from the heat loss, the escape of such vapor from the hot Well is objectionable and undesirable in many installations.

One of the important features of the invention is that water is pumped to the heating coil at a rate in excess of the maximum steam generating capacity of the unit, whereby all overheating and possible burning out of the coil is avoided.

Another important feature of the invention is that the excess liquid above a given maximum level in the steam separator, instead of being trapped-olf into a hot well, is conducted from the steam trap directly to the intake chamber or intake manifold of a feed pump and reintroduced into a heating coil or equivalent means.

Still another feature of the invention is the disposition of a check valve on the discharge side of the steam trap to prevent back-lling of the steam separator when the apparatus is initially started.

Another feature of the invention is the provision of means for condensing any steam that may be present in the intake manifold of the feed pump to prevent vapor-locking of said feed pump. Such feed pump is claimed in application Serial No. 746,189 filed on May 6, 1947, which is adivision of the instant application.

A further feature of the invention is the use of. a centrifugal pump serving in the dual capacity of a make-up water pump and a circulating pump for the heat exchange means associated with the intake manifold to prevent vaporlocking of the feed pump. A check valve associated with said centrifugal pump prevents the trapped-out liquid from the separator from backing up into said pump.

, A further feature is the use of a relief valve on the outlet side of the steam trap set to open at a ypressure lower. than that normally maintained in the steam separator so that a pressure differential exists upon the opposite side of said steam trap assuring satisfactory operation of said steam trap at all times.

A still further feature of the invention is that excess liquid is taken from the lower end of the steam separator and is recirculated through the heating coil and the amount of liquid trappedout of the steam separator through the steam trap is thus materially reduced.

Other objects and feeatures of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings, in which:

Figure 1 diagrammatically illustrates a steam generating system vembodying the principles and advantages of the present invention;

Figure 2 is an enlarged view, partly in elevation and partly in section, taken on the line 2-2 of Figure l, and particularly illustrating the check valve arrangement associated with the intake chamber or manifold on the inlet side of the feed pump;

Figure 3 is a sectional view through the intake manifold, taken on the line 3--3 of Figure 1, particularly showing the arrangement of the heat exchange tube for condensing any vapor that may be present in the intake manifold to thereby prevent vapor-locking of the feed pump;

Figure 4 is a sectional view taken on the line 4-4 of Figure 2; and

Figure 5 is a sectional view taken on the line 5 5 of Figure 2.

Referring now to Fig. 1 of the drawings, the numeral l generally indicates a combined pump means which provides a feed water supply pump F and a recirculating pump R. The`pump measn l is driven by a motor 2 through -a belt 3. The motor 2 also drives a blower 4 through a belt 5. The blower 4 is connected by a suitable conduit 6 with an air inlet chamber 'l of a steam generating unit generally designated by the numeral 8. The steam generating unit 8 comprises a suitable burner nozzle 9 to which fuel is supplied through a conduit 9a. Fuel from the nozzle 9 is sprayed into a combustion chamber Ill contained within a housing Il and is ignited by suitable electrode means I2. The housing II contains a heating coil or steam generating unit I3 of the vpancake type through which the liquid to be heated is circulated. A flue I4 is provided at the upper end of the housing Il for the escape of the products of combustion.

The feed pump F includes an intake feed manifold I5 and an outlet feed manifold I6 inter-V connected by identical housings l1 containing inlet check valves I8 and I9 (see Fig. 2), which housings will be described in greater detail hereinafter. The intake feed manifold I is connected by a pipe line with the discharge opening 2| of a centrifugal or make-up pump 22. The centrifugal pump 22 isdriven by a motor 23 through a belt 24. The inlet opening 25 of the centrifugal pump 22, is connected by a pipe 26 with a feed water tank 21 containing water at a temperature low enough so that no vapors arise therefrom. A predetermined minimum water level is maintained in the feed water tank 21 by a float mechanism 28 operatively associated with a float-controlled valve 29 and a water supply pipe 3D.

The pipe line 20 has a pressure gauge 3| connected therein adjacent the intake feed manifold I5 and a one-way check valve 32y arranged between the centrifugal pump 22 and the pressure gauge.3|. The check valve 32 is connected in `the pipe 20. so as to allow fiowv therethrough only in a direction toward the intake feed manifold I5. A manually operated shut off valve 20,8. is. connected-in the pipe line 2U on the inlet side of the checkV valve. 32. A cross-fitting 33 is connected in the pipeline 20 between the pressure gauge. 3|.and theA check valve 32. The up.- perA opening of the crossetting 33 is connected with a pressure relief valve 34, the outlet of which valve is.connected by apipe 35 with the feedwater tank 21. A conduit 36 has one end thereof connected with the. stem of a pipe-T 2|)b inserted in the pipe line 2|). at a point between the. centrifugal pump 22 and the manual valve20.-and has its` otherend connected with heat exchangeuneans. in the form of a cooling tube, 31 whichextends through the intake feed manifold I5, as isbestshown in Figs. 1 and 3. Aleak-proof joint is provided between the out,- sideof thetube 31 and the manifold I5 by suitablestufng. boxes 38; at each end of said manifold. The inlet end of the cooling or heat exchange tube 31; is connected to the conduit 35 and the Aoutlet end of said tube is connected by I a. conduit39: with thepipe 35 goingrto the feed .water-tank 21rfrom the relief valve 34. An adjustable needle valve 46 is connected in the conduit 39:.to. controlithe rate or volume of fluid thatcan pass through theheat exchangetube 31.

Referring now to Figs. 2 and 5, the check valve housings. I1;areI identical in construction and a description of one will therefore ,suffice for both. The housing,y I1 has an inlet opening 4I (Fig. 5)

whichiscounterbored as indicated at 42 to Are.- f

ceive` aA bushing 43. The intake feed manifold ISqhasanoutlet opening 44 which is counter-,- bored at 45 to receive the bushing 43. The bushing 43 .thus serves to align the housing I1 with theintake manifold I5. A stud 46 is threaded intothe housing I1 and projects through an opening 4.1:in the manifold |5.. Acapnut 48 is. mounted uponthe outer end of the stud 46 and secures the housing and manifold'together in assembledrelation. Suitable sealing means 49 .ls interposed between theV confronting faces of the housing I1 and manifold I5 to avoid leak.- age and a suitable gasket 50 .is disposed between thecap nut 48.and the manifold I5.

The opening 4I in the housing I1 communicateswithapassageway 5I (Fig. 2) controlled by. thecheck valve. I8. previously referred to. The check valve I8 is normally urged toward its seata52 by a conical spring 53. The housing I1 ls furtherprovided with a chamber 54 and the 4 check valve I8 controls the flow of liquid from the passage 5I into the chamber 54. A bleeder valve 55 is mounted in the housing I1 directly above the check valve IB and provides a means for venting air from the chamber 54 when the pump means is first started.

The housing I1 is still further provided with an opening 55a (Fig. 2) adapted to communicate with the chamber 54 when the check valve I9 is raised from its seat 56. A- spring 51 normally tends to maintain the check valve I9 closed. A removable plug 58 is disposed in an opening 59 directly above the check valve I9. As will be apparent from Fig. 4, the opening 55il communicates with the outlet feed manifold I6 and said manifold is aligned with the housing I1 by a bushing 60 similar to the bushing 43. A stud 6| is threaded into the housing I1 and a cap nut 62 Von the outer end of the stud secures the manifold I6 to the housing I'I. Suitable sealing-means 63 `is disposed between the confrontingfaces of the housing I1 and the manifold I6 anda suitable gasket r64 is disposed between the manifold IGnand the cap nut 62. One end of the outlet feedmanifold I6 is closed by a plug 65 and its opposite end is connected to a pipe 65.

A standpipe |51- (Fig. 2), is threaded into an opening68 in the housing |1 and communicates at its upper end'directly with theV chamber 54. Normally1 the standpipe 61 is filled with water and provides aV water column through which pulsations from the pump means I are transmitted to any liquid contained in the chamber 54. The pump means I may include any suitable elements, such as a diaphragm (not shown) for producing pulsations in the standpipe 61 to produce a pumping action.

It will be apparent from the description thus far, that the water introduced into the intake feed manifold I5 through the pipe 20 will enter the opening 4| in the housing I1 and flow into the passageway 5| the check valve I8 opening in response to the pressure of such liquid to admit the same into. the chamber 54 between pulsationsr in the standpipe 61 and fill said chamber. Hence, upon the next pulsation imparted to the liquid columnin the standpipe 61, a certain amount-of the water will be displaced from the chamber 54-and forced past the check valve I9 intol the opening 55a from whence it will fow into the outlet feet manifold I6'and into the pipe 66.

The recirculating pump Rof the pump means includes an intake recirculating manifold I5* and an outlet recirculating manifold I6? (Fig.v1). These manifolds are generally similar to the manifolds |5.- and I6 previously described, except that theY inlet recirculating manifold I5a is not provided with a heat exchange tube and is closed at one end by a .plug |5b; Theoutlet recirculatingmanifold I6u isclosed lat one end by a plug |61. The manifolds I5a and I6a are interconnected by housings I1a similar to the housings I1previously described and itwill. be understood that the housings |1n contain check valves similar to the check valves I8 and I9 already described. It will also beunderstood that vthe housings I1a have standpipes (not shown) which function like the standpipes 61 to provide a pumping action to effect recirculation of the excess lquidas will be described hereinafter.

The inlet recirculating manifold I5l is connected by a pipe 10 with the lower end of a steam separator 1|. A manually controlled valve 12 inthe line,.10fserves to cut off-communication between the steam separator 1I and the recirculating pump R. A strainer 13 is connected in the pipe line and serves to prevent the passage of any foreign matter from the steam separator 1I through the pipe 10 into the inlet recirculating manifold |58. A strainer cleanout valve 14 is connected to the strainer 13 as shown.

The outlet recirculating manifold II8L is connected by a pipe 15 with a conventional mixing chamber 16. The pipe 66 from the outlet feed manifold I6 is also connected with the mixing chamber 16. The mixing chamber 16 is, in turn, connected by a pipe 11 to theinlet end 18 of the heating coil I3. A manually controlled shutoff valve 19 connected in the pipe 11 controls the flow of liquid to the heating coil I3. Hence, it will be clear that feed water supplied through the pipe 66 and recirculating water supplied through the pipe 15 will be brought together in the mixing chamber 16 and then delivered to the heating coil I3 through the pipe 11. A pressure gauge 18a indicates the pressure on the line 11 going to the heating coil I3. A valve 88 is connected with the mixing chamber 16 for effecting blowing-down of the heating coil I3.

The outlet end of the heating coil I3 is connected by a pipe 8| (Fig. 1) with the steam separator 1I, so that the heating coil discharges into the upper portion of said steam separator and any of the liquid not ashed into vapor in said steam separator collects in the bottom thereof, and the level of said liquid is indicated by a gauge glass 82. In order to prevent the liquid level in the steam separator 1I from rising above a predetermined height, one end of a pipe 83 is connected to said separator at a level corresponding to the maximum desired liquid level in the separator, and the other end of said pipe is conveniently connected with the lower opening of the cross-fitting 33. The pipe 83 has a manually operable shut-off valve 84 connected therein on the inlet side of a. steam trap 85. A one-way check valve 86 is connected in the pipe 83 between the steam trap 85 and the cross-fitting 33. The check valve 86 is installed The pipe line 81 is connected with a load diagrammatically indicated at 89. A condensate return pipe 98 returns condensate from the load to the feed water tank 21. The steam separator 1I is also provided with a pressure gauge 9|, a safety valve 92 and a blowoi or drain valve 93. y Y

The operation of the apparatus from a cold start is as follows:

The motors 2 and 23 are preferably so arranged that both start simultaneously. Hence, the pump means I, which handles both feed water and recirculating water, will start simultaneously with the centrifugal pump 22. The capacity of the pump means I exceeds the maximum steam generating capacity of the unit 8 so that an excess of water is supplied to the heating coil I3 and avoids all possibility of said heating coil burning out, and the capacity of the make-up pump 22 greatly exceeds that of the feed side F of the pump means I so that water can be withdrawn through the pipe 26 from the feed water tank 21 at a rate greater than the ,said feed pump F can handle the same. Such water will be forced past the check valve 32 in the pipe line 2D and will enter the intake feed manifold I5 and passage 5I in the housing I1 from whence it will flow (between pulsations in the standpipe 61) past the spring-pressed inlet check valve I8 into the chamber 54. The pulsations will force this water past the check valve I9 into the outlet feed manifold I6, through the pipe 66 and into the mixing chamber 16. The water will then be conducted by the pipe l11 to the inlet end 18 of the heating coil I3. `When the coil I3 is filled, water will be discharged through the pipe 8| into the steam separator 1|, and the fact that the coil I3 is lled will be indicated by the rise of level of the water in the steam separator I I, as indicated by the gauge glass 82. Back-llng of the steam separator 1| is prevented at this time by the one-way check valve 86 in the pipe line 83. which is maintained closed by the pressure created by the centrifugal pump 22. Any water delivered to the steam separator 1I will be conducted through the pipe line 18 to the intake recirculating manifold I5 and will be pumped through the housings I1a into the outlet recirculating manifold I6a from whence it will be conducted by the pipe 15 to the mixing chamber 16, as will be readily understood, so that both feed and recirculating water will now be supplied to the heating coil through the pipe 11. While such recirculation is occurring, the burner 9 is started and the coil I3 is heated.

Meanwhile, water. will continue to be supplied by the feed pump F and will be Withdrawn from the steam separator 1I and recirculated by the recirculating pump R until the liquid in the heating coil I3 is heated to a point where at least a portion of it will flash into steam when introduced into the steam separator 4. The gauge 9| will indicate the steam pressure in the separator 1I. As the pressure increases in the steam separator and should the level of the liquid in said steam separator rise to a height above the connection of the pipe 83 therewith, the liquid will be trapped-out of said steam separator through the steam trap 85 and will pass through the pipe line 83 into the pipe 29 connected with the intake feed manifold I5. During this portion of the cycle, if the water discharged from the steam trap 85 is under a greater pressure than that developed by the centrifugal pump 22, the check valve 32 will close, preventing any back-surging into said centrifugal pump. The centrifugal pump 22 will then slip" to any extent necessary to compensate for the reduction in the volume of its discharge caused by complete or partial closing of the check valve 32.

Due to the steam vapor accompanying the water discharged through the steam trap 85 and delivered through the pipes 83 and 28 to the intake feed manifold I5, or to the flashing of the heated liquid as the result of a reduction of pressure, it is possible for some vapor to occasionally enter or to form in the intake feed manifold I5 and cause a vapor-lock at the inlet check valves I8. Ordinarily, the feed pump F would remain vapor-locked only until the steam condensed, but such delay is undesirable and could prove detrimental to the operation of the steam generatingapparatus because the interruption of a continuous flow of water to the heating coil I3 would result in overheating and possible burning out of said coil. By circulating cooling water from the feed water tank 21 through the heat exchange tube 31 (by means of the centrifugal *avoided Incidentally; the'heat-absibedfby the liquid vvpumped through the 'heat exchange tube 4 31 is not Ylost I4'beca-usey said liquidl -is'retu`rne"d to fthe-"feed'w'ater -tank-2'1.

-Thet'ndencyffr ra \f`a"`rl `)ck to V-formeas a I result'r of dashing due to f a' pressure-dren `will '"be 'apparent Whe'nV-'the Efact 'is considered that heated lliquidniaybe trappedback from th'e'steam Separator T1 I *at af-press'ure of labout 100 lbs 'and 'fatatemperature offabout`3`37 F. Evena'slight "pressure 'dropinfthe v'intake feed manifold I5 Will permit Some of this liquid `to-flashf into-stam. `Onthe other `hand, `the water'which -is passed through the 'heat-exchange tube 31 istakenfrom thefediivater tank 21 which contains 'water-ata -relatively lowy temperature of Yabout-115,-andvv this-f temperature is sumcientto condense'any vapor in the manifold I5. Asha's-been pointed utb'eforejthe discharge end ofthe heat exchange t'ube V31 is `connected with Athe feed water `tank 21 by the conduitf39 so that theCentriug'al'pump'ZZ inf effect-circulates the 'feed zwater through "tithe heatexchan'ge" tube 31.

'By'wayof contrast, noheat exchange tube is `I iece'ssar'y in 'I the intake recirculating 'manifold I5* *because "the `liquid 'entering said 'manifold issubjectto the' pressure inthe steam separator 1I and hence no pressure drop can' occur in said manifold which 'would cause any flashing of the liquid into steam and vapor-lock the recirculating pump R.

As'the steampressure isl builtu'p in the's'te'ain separator 1I and the steam iswithdrawn'from vthe top of said steam separator toc meet'fa-given demand, the liquid level in said sepa1'ator may 'drop beloiv the level of the pipeline 83, in-whic'h event no water 'will be trapped-back fromthe separator through -the 'steam trap 85. This'will result in a reduction in theV pressure inthe pipeline 83 on the outlet side of "theste'am trap'85 'l so that the pressure tending to close the check valve 32 becomes less' and when this pressure vis `exceeded by the pressureV developedbyithe centrifugal or make-up pump '22, thecheck valve 32 will open andthe pump22"Wi'1l thenfresuine 'supplying feed Water from the tank'21'tothe y:feed pump F.

The relief valve 34 is provided'to' prevent' equalization 'of the pressure the' steam separator 1I with the vp'ressu'reat theinta'ke'feed manifold 'dered ineffective. Accordingly,"the relief valve34 is adjusted to'pe'n at a pressurethat'will alvWays insure `a differential 'suchas'to permit the steam trap 85 tofunction and prevent the `liquid level "in vthe 'steam separator 1I 'from 'risihg'too' none of the heat content f t-heliquid trappedout of the steam separator 1I is lost, because this liquid is immediately delivered to the intake feed manifold I5, where, if it is vcon'nnir'igled with make-up Water, it will heat such water, and such heat as is 'taken out of the trapped liquid 'and `Itisto beunderstood that a'conventinal vpressure switch (not shown) -inay beconnected with thelsteam separator '1I to automatically "control fthe @operation of fthe motori 2, which drives the feed arid"recirc' u latingv pump vmeans I, s'o that' the "pumpmeanswill bestop'ped when Aa predetermined maximum pressure isI attained in the steam 20 `j separatr 1 I However, the centrifugal pump 22 is preferably'arranged so that it will operate'connozzle 9 may b e controlled or modulatedinlac- 'cordance With thestearn demand by" any suitable control means.

While aheating coil 'I3 has been-shownas ja 'means forI heating the'liquid, it will be understood Ytl'iat such' heatingv coilv is notc'ritical and that the principles ofthe syst'em'jare 'equallyapplicable to boilersioflheader and tubeV construction. It Will yalsobe HA'apparenttliat*the'invention is not restricted to the 'particular form ofA heat exchange vmeans associated with thefeed pumpto prevent 'vapor-locking thereof. Moreover, it will also'be 'apparent that Laseparate feed :pump and a separate recirculation: punipjwith a motorv for' driving each (not Shown) ,maybe used in lieu of menombned'fed pump and recirculating'pump and; the

"single motor drive therefor presently shown; 'all Without departing frein-the-v spirit of-the invention orthesco'pe off the" annexed'claims.

I* claim: 17.-Stea-'m 'generating vapparatus comprising:

lconduit means a'dapte'dto receive a liquidto-be heated, said conduit means having an 'inlet'and ed liquid directly from said steam separator to pipe line and connected withsaid/feedpumpfor coolingsa'id" feedpump inlet to'prevent vapor 4locking of sai-d' feed pump.

`2. 'Steam *generating yapparatus comprising:

conduit-'means adapted -to receive' a liquid to be fheated, said' conduit means vhaving 'an inlet kand "an outlet' means for heating said conduit means; af feed 'pumpv for pumping liquid into the inlet of Said' conduitmea'ns;v said feed pump having an intakechainber; a steamseparator connectedwith theputletoffs'ad conduit means; a continuous I'pipe line connected with "said steam Aseparator having 'one'end thereof communicating with said steamseparator at apredetermined maximum "desired liquid llevel fand the other end thereof 'c'onnectedwith said feedpurnpintake chamber;

a steam trap in said pipe line for passing heated liquid and accompanying vapor from said steam separator directly to said feed pump intake chamber; and means independent of said pipe line for cooling said intake chamber to condense any vapor that may be present therein and thus prevent vapor-locking of said feed pump.

3. Steam generating apparatus comprising: conduit means adapted to receive a liquid to be heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including an intake chamber and a spring-pressed inlet check valve in said intake chamber; a steam separator connected with the outlet of said conduit means; a continuous pipe line connected with said steam separator having one end thereof communicating with said separator at a predetermined maximum desired liquid level and the other end thereof connected with said feed l*pump intake chamber; and a steam trap in said pipe line for passing heated liquid and accompanying vapor through said pipe line from said steam separator directly to said feed pump; and

means independent of said pipe line and connected with said intake chamber for cooling said intake chamber to prevent vapor-locking of said inlet check valve.

4. Steam generating apparatus comprising: 3

conduit means adapted to receive a liquid to be heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including I pump intake manifold; a steam trap in said pipe line for passing heated liquid and accompanying vapor from said steam separator directly to said feed pump; and heat exchange means independent of said pipe line connected with and having at least a portion thereof disposed in said intake manifold for condensing any steam that may be present in said intake manifold and thereby prevent vapor-locking of said inlet check valve.

5. Steam generating apparatus comprising: a heating coil having an inlet end and a discharge end; means for heating said coil; feed pump means for pumping liquid into the inlet end of said heating coil, said feed pump means including an intake manifold and an inlet check valve controlling the flow from said manifold; ka steam separator connected with the discharge end of said heating coil; a pipe connecting said steam separator with said feed pump means arranged to conduct liquid at a ygiven level from said steam separator to said intake manifold; a steam trap connected in said pipe for passing heated liquid and accompanying vapor from said steam separator to said intake manifold; heat exchange means in said intake manifold for condensing any steam that may be present in said intake manifold and thereby prevent vaporlocking of said inlet check valve; means for supplying make-up water to said inlet manifold; and means for diverting a portion of said make-up 10 Water and introducing the same into said heat exchange means. y Y

6. A steam generating apparatus comprising: a heating coil having an inlet end and a discharge end; means for heating said coil; feed pump means for pumping liquid into the inlet end of said heating coil, said feed pump means including an intake manifold and a spring-pressed check valve arranged in a passageway communicating with an outlet of said intake manifold; a steam separator connected with the discharge end of said heating coil; a pipe connecting said steam separator with said inlet manifold; a steam trap connected in said pipe, said steam trap serving to pass heated, excess liquid above a given level from said steam separator to said intake manifold; a centrifugal pump for supplying make-up water to said intake manifold; a heat exchange tube in said intake manifold for condensing any steam that may be present in said intake manifold and thereby prevent vapor-locking of said inlet check valve; and a conduit for cooling liquid having one end connected with the discharge side of said centrifugal pump and its other end connected with one end of said heat exchange tube.

7. Steam generating apparatus comprising: conduit means adapted to receive a liquid to be heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including an intake chamber; a steam separator connected with the outlet of said conduit means; a pipe line having one end connected with said steam separator and having its other end communicating with said intake chamber; a steam trap connected in said pipe line for passing heated liquid and accompanying vapor from Isaid steam separator to said intake chamber; 'a feed water tank; a second pump having inlet and discharge openings; a pipe line connecting said feed water tank with the inlet opening of said second pump; means for cooling said intake chamber to condense any vapor that may be present therein; a supply conduit having one end communicating with the discharge opening of said pump and its other end communicating with said heat exchange means; and a return conduit connecting said 'heat exchange means with said feed water 'tank,'whereby the water from said feed water tank is circulated through said heat exchange means to prevent vapor-locking of said feed pump.

8. Steam generating apparatus comprising: conduit means adapted to receive a liquid to be' heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including an intake manifold; a steam separator' connected with the outlet of said conduit means; a pipel line connected with said steam separator having one end thereof communicating Withsaid steam separator at a predetermined point above the bottom of said steamseparator corresponding to the maximum desired liquid level to be maintained in said steam separator and having the other end thereof communicating with said intake manifold; a steam trap in said pipe line, said pipe line normally conducting liquid from said steam trap directly to said intake manifold; vmeans independent of said pipe line for cooling said intake manifoldv to prevent vapor lock-ing thereof; a one-way check valve in said fpipe line between said steam trap and' said intake manifold arranged to allow flow only in a -directionfrom-.said steam trap toward said intake .manifold and means for supplying liquid to said :intake manifold of said feedY pump, said check 'valve preventing'back-iilling of liquidfrom said .intake manifold into said steam separator during the initial starting of the apparatus.

-9.- Steam generating apparatus comprising:

conduit means adapted toxreceive a liquid to be heated, saidconduit means having an inlet and an outlet; .means for heating said conduit means;

.-feedpump means for supplying liquid to the inflet of said conduit means; Va steam separator connected'withthe outlet of said conduit means;

la. pipe line connecting said steam separator with said Lfeed.pump'means; a centrifugal pump for pumping liquid -to the intake ofsaid feed pump -meansyand a one-Way check valve between said `centrifugal pump and said feed pump means ar- .ranged to allow flow only ina direction away ,fromfsaid centrifugalA pump, whereby when the 'pressure of the liquid from said steam separator=exceeds the pressure ofv said centrifugalpump. Ysaid-check valve will remain closed and said centrifugal pump will slip.

-,'10.-Steam generating apparatus comprising:

Aconduit-means Vadapted to receive a liquid to` be heated, said conduit -means having an inlet and an outlet; means for heating said conduit means;

atfeed-'pump forpumping liquid into the inlet .of said! conduit means, said feed pump including: an intakemanifold; a` steam separator connected with the^outlet ofrsaid conduit means;

a pipe line connected withsaid steam separator .having one end thereof communicating with said steam separator at-a predetermined point above the l'bottom of said-steam separator corresponding to the maximum desired liquidlevel to be maintainedin-said' steam--separator'and having the other-end thereof communicating with. said intake manifold; a` steam trap in said'pipe line for. passing heated liquid and accompanying vapor` fromv said separator to said intake manifold;

a make-up pump for supplying liquid to said intakeA manifold; av check-valve arranged between said make-up pump and said intake'manifold, said check Avalve being-arrangedto be opened only -Iwhen the pressureof the liquid trapped through said steam. trap is lower than thepresf sure of the make-up liquid delivered to' said intake manifold by said vmake-up pump.

11. Steam generating .apparatus comprising: conduit means adapted to receive a liquidztobe heated,v said conduit means having an inlet and an outlet;1means' for heating said conduit means; feed pump mea-ns for supplying liquid to the inlet of :saidconduit'meansv a steam separator connected with the outlet of said conduit zmeans; a pipe. line connecting saidlsteam separator'with saidfeed pump.zmeans;said pipeline having its point of connection'with said steam separator'at a means adapted to receivea liquid to be'heated, said conduit means having an inlet and an out- `let;smeans for heatingv said conduit means; feed pump; means for supplying liquid to the inlet of said Vconduit'means; asteam separator connected 'withthe outlet of said conduit means; a pipe .line connecting saidsteam vseparator with said feed pump means,said pipe line having. itspoint of Aconnection with'said steam .separator at-a given; predetermined height to maintain' a given 4maxin'ium water-level insaid steam separator; a steam .trap connected in said pipeline for trap- .ping-out liquid `from said steam separator Ato vsaid feed; .pump means; a centrifugal., pump for pumping make-up liquid to the intake ofsaid .feedpump means; and acheck valve arranged between said centrifugalpump and said feed Apump means, whereby vwhen the pressure ofthe liquid trapped through said steam trap exceeds the pressure developed by said centrifugal pump. saidcentrifugal pump will slip and said feed pump means will pump said trapped-out liquid into the inlet of said conduit means.

. 12. Steam generating apparatus comprising: conduitmeans' adapted to receive a liquid to be heated,.said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pumpincluding van intake manifold; a steam separator connected with thev outlet of said conduit means; a pipe line connected with said steam separatorhaving one end-thereof communicating with said steam. separator at a predetermined pointabove the bottom of said steam separator correspond- Ying to the maximumy desired liquid level tofbe maintained insaidsteamfseparator andhaving the-:other 'end thereof communicating 'with said intake manifold; a steam trapinsaid pipe line for passing heated liquid and accompanying vaporfrom said separator to said intake manifold; a one-way check valve in said pipe line'betweensaidsteam trap-and said intakev manifold; a make-up pump connected with said pipe? line for supplying Amake-up liquid .to Vsaid intake manifoldsaid check valve beingarrangedto pre-- vent back-filling -of liquid into said steamy separator duringthe: initial starting of the apparatus a second check valvevadjacent said make-iup pump,said second check valve beingarrangedto be opened during-` operation of the4 apparatus only when the-pressure of the ,liquid trapped through saidsteam trapis Ilower than the pressure of the make-up liquid :delivered by Vsaid make-up pump.

-13. Steamc generating apparatus as defined vin claim l2, inwhicha` relief valve is arranged between'thetwo check` valves, said relief valve being set to open at a pressure' substantially less than that -normallymaintained in said steam'separator, whereby a pressure differential is maintained-.on the opposite sides of said steam trap. conduit' means adapted to receive a liquid to ybe heated, said conduit means having an inlet and an outlet; Vmeans for vheating said'conduit mea-ns; afeedapump for pumping liquid into the inlet of said conduit means, said feed pump including f an intake manifold; a steam separator connected with the `outlet of said conduitY means; a pipe line connected with saidsteamseparator having one end thereof communicating'with said steam separator and having the other end thereof communicatingwith said intake manifold; a steam trap in said'pipe: line for passingheated liquidand accompanying vapor from said' steam separator to said intake manifold; and a'relief valve connected inl said pipe line between said steamtrap and saidI intake manifold, said relief valve being set to openat a pressure substantially less than that normally 1 maintained in said f steam separator, whereby ay pressure differential is maintained on the opposite sides `of said steam vtrap assuring satisfactory op eration thereof.

' 15..Steam generating v:apparatus comprising: conduit means'zadapted to receivela liquidto be heated,-said'conduit means having an vinlet-'and an-outlet; meansfor heating said conduit means: a. feed pump for pumping liquid `into the inlet'f-of said conduit means; a steam separator connected with the outlet of said conduit means; a pipe line connected with said steam separator having one end thereof communicating with said steam separator at a predetermined point above the bottom of said steam separator corresponding to the maximumdesired liquid level to be maintained in said steam separator and having the other end thereof connected with said feed pump; a steam trap in said pipe line for passing heated liquid and accompanying vapor from said separator to said intake manifold; a one-way check valve in said pipe line between said steam trap and said intake manifold, said check valve being arranged to allow now only in a direction from said steam trap toward said intake manifold; and a pressure relief valve Vconnected in said pipe line, said pressure relief valve being arranged to open at a pressure lower than that normally maintained in said steam separator.

16. Steam generating apparatus comprising: conduit means adapted to receive a liquid to be heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including an intake manifold and a spring-pressed inlet check valve arranged in a passageway communicating with an outlet of said intake manifold; a steam separator connected with the outlet of said conduit means; a pipe line connected with said steam separator having one end thereof communicating with said steam separator at a predetermined level above the bottom of said steam separator and having the other end thereof communicating with said intake manifold; a steam trap in said pipe line for passing heated liquid and accompanying vapor from said steam separator to said intake manifold; a feed water tank; a make-up pump for pumping water from said tank and supplying the same as make-up water to said intake manifold, said make-up pump having inlet and discharge openings; a pipe line connecting said feed water tank with said inlet opening of said make-up pump; heat exchange means in said intake manifold for condensing any steam that may be present in-,said intake manifold and thereby prevent vapor-locking of said inlet check valve; a conduit having one end connected with said discharge opening of said make-up pump and its other end connected with one end of said heat exchange means; and a return conduit connecting the other end of said heat exchange means with said feed water tank.

17. Steam generating apparatus as defined in claim 16, in which a recirculating pump is connected with the lower end portion of the steam separator and with the inlet of the conduit means for recirculating the liquid in said steam separator through said conduit means.

18. Steam generating apparatus comprising: conduit means adapted to receive a liquid to be heated, said conduit means having an inlet and an outlet; means for heating said conduit means; a feed pump for pumping liquid into the inlet of said conduit means, said feed pump including an intake manifold; a feed water tank; a centrifugal pump having inlet and discharge openings; apipe line connecting said feed water tank with the inlet opening of said centrifugal pump; a pipe-line connecting the discharge opening of said Ycentrifugal pump with said intake manifold; a loneway check valve in Asaid pipe line arranged to allow flow only in a direction from said centrif- 14 ugal pump toward said intake manifold; a steam separator connected with the outlet of said conduit means; a pipe line having one end connected with said steam separator at a predetermined height to maintain a given maximum water level in said steam separator and having its other end communicating with said intake manifold; a steam trap connected in said last-mentioned pipe for passing heated liquid and accompanying vapor from said steam separator to said intake manifold; a check valve in said last-mentioned pipe line between said steam trap and said intake manifold; a relief valve connected in said lastmentioned pipe line between said check valve and said intake manifold, said relief valve being set to open at a pressure substantially less than that normally maintained in said steam separator so that a pressure differential is maintained upon opposite sides of said steam trap; a heatA exchange tube in'said intake manifold; a conduit for conducting liquid from the discharge side of said centrifugal pump to one end of said heat exchange tube; a conduit connecting the other end of said heat exchange tube with said feed water tank; a needle valve connected in said last-mentioned conduit for controlling the rate of iiow of cooling fluid through said heat exchange tube; means for maintaining a predetermined water level in said feed water tank; and a recirculating pump for pumping liquid from the lower end of said steam separator to the inlet of said conduit means.

19. Steam generating apparatus comprising: a steam generating system including conduit means adapted to receive a liquid to be heated and a sump for condensate from said system; a pump for pumping liquid into the inlet of said conduit means, said pump including an inlet check valve and an inlet chamber ahead of said check valve; a conduit connected with said system for returning liquid at steam forming temperature to the inlet chamber of said pump; a heat exchange tube extending into said inlet chamber for cooling the heated liquid returned thereto to thereby prevent vapor-locking of said inlet check valve; packing means around said heat exchange tube for preventing the escape of fiuid from said inlet chamber; and means interconnecting said tube with said sump for circulating the sump liquid through said tube to effect said cooling.

20. Steam generating apparatus, comprising: a steam generating unit adapted to receive a liquid to be heated, said unit having an inlet and an outlet for the liquid to be heated; means for heating said unit; a feed pump having the outlet thereof connected with the inlet of said unit for pumping liquid into said unit at a rate in excess of the maximum steam generating capacity of said unit; a steam separator connected with the outlet of said unit; a conduit interconnecting said steam separator with the inlet of said feed pump for conducting excess heated liquid from said steam separator directly to the inlet of said feed pump; and means independent of said conduit connected with said feed pump inlet for passing a coolant therethrough to cool said feed pump inlet to prevent said excess heated liquid from Causing vapor-locking of said feed pump.

21. Steam generating apparatus, comprising: a steam generating unit adapted to receive a liquid to be heated, said unit having an inlet and an outlet for the liquid to be heated; means for heating said unit; a feed pump having the outlet thereof connected with the inlet of said unit for 1 5Y pnmvinsrliquidiinto y-said..ur1it;at;y errate;irifexcess` of theal maximumsteam generatingi capacity of; said unit; a; steam.--Separatorconnected Awith the outlet, ofl said uuit; a; conduit interconnecting saidsteam separatorrandsaidffeed pump for con. ducting; excess; heated, 1iquid from said steamseparatorg directlyto ,the inlet of saidr feed; pump; afeed-watertank connectedzwith said feed-pump; andgmeaus for-withdrawing liquid from saidfeed watertankl anddelivering-V the same to said Vfeed4 10 pumpginlet toeect cooling of sa-idexcess heated liquid toprevent vapor-locking vof -said feeclpumpA inlet.

22. Steamagencratingapparatus, comprising; a

steam generator unit` adapted'to receive aliquid 15,y

torbe heated, said unitl havingan'inletand-gan; outlet for theliquid to beheated,meansforheating said unit; a feed` pumpA having the outlet; thereoiconnected withtheginletof saidv unit for pumping liquid into said unit; asteamseparator- 20 connected with the outlet;of said unit; conduit means interconnectingsaid steam Separatorand said 4feed vpump for conducting-'heatedliquid from said-,steamseparator directly tothe-inlet of ,jsaid Watergtank to the inlet of said feedpump in heatf transfer relation-Withsaid heated liquid for e901-,v ing'v said heatedv liquidy suficientlyr to, preclude vapor-locking of 1 saidgfeed pump.

PERRY ARAN T.

REFERENCES CITED Theffollowing references are' of record inthefile ofzthis patent:

UNITED STATES PATENTS Number Name` Date 1,939,415 Schaub Dec. 12,1933 2,054,710 Okada Sept. 15, 1936 2,227,349 Kerrick A A I Dec. 31, 1940 2,259,361' Vorkauf, Oct. 14, 1941 2,306,298 Curtis Dec. 2,2, 1942 FOREIGN PilTENTsv Number Country Date 255,425'` GreatBrtain Mar. 31,1927 

